This invention relates to a wrap-around closure assembly for elongate objects. More specifically, this invention relates to a closure assembly including a heat recoverable closure member and a fastening means.
It is often advantageous to provide wrap-around insulation, protective closures, bundling assemblies or joint seals for elongate conduits, pipes, cables and the like which do not have a readily accessible end over which a conventional tubular closure can be drawn. In such instances, a split closure member has often been employed. The split closure is wrapped about the substrate and the two edges are then held relative to one another. Preferably some sealing device has been employed at the edges to prevent environmental intrusion. Often the closure member is of a heat recoverable material and once the edges are fixed relative to one another, the heat recoverable material is brought to the temperature of recovery. The closure member then contracts to tightly conform to the substrate in a tensioned condition.
A number of such wrap-around closures have been developed in an attempt to satisfy particular use requirements and at the same time provide an inexpensive, easily assembled closure means giving a high degree of reliability in use. Examples of such wrap-around closures fabricated from heat recoverable material are described in U.S. Pat. No. 3,379,318 to Conde; U.S. Pat. No. 3,455,336 to Ellis; U.S. Pat. No. 3,530,898 to Wilson; U.S. Pat. No. 3,542,077 to Muchmore; U.S. Pat. No. 3,770,556 to Evans et al; U.S. patent application Ser. No. 603,636, filed Aug. 11, 1975, to Jervis; U.S. patent application Ser. No. 436,674, filed Jan. 25, 1974, to Naidoff and U.S. patent application Ser. No. 530,687, filed Dec. 9, 1974 Biddell, all assigned to the assignee of the present invention. These several disclosures are all incorporated herein by reference
In spite of the success of the aforementioned wrap-around closure members, certain difficulties remain. Some of the prior devices have required special fabrication of the edges of the sheet-like closure members to accommodate the specific fastening means employed. Such special fabrication includes ridges at each edge, button and buttonholes, interlocking members and the like. These specially fabricated edges in most instances require that the width of the closure member be predetermined for a specific size of substrate. Closure members cannot be cut to size in the field when a special edge is employed. Furthermore, added fabrication steps, die complexities and the like are also required in the production of closure members with special edge requirements. Naturally, the fabrication of a simple sheet as a closure member is far more advantageous and inexpensive.
Prior closure assemblies have also often necessitated special assembly techniques requiring careful attention to detail to insure a proper closure. With certain closure members, modifications must be performed in the field. Such modifications are time consuming and may lead to improper assembly. Other closure devices require a close-fitting of a fastening means over the closure member. Such close fits lead to difficulty in assembly and increase the possiblity of error in either manufacturing or assembly resulting in the effecting of an incomplete closure.
When heat recoverable closure members are employed, another difficulty arises in completing the closure. Once the closure member has been assembled with the fastening means, it is necessary to heat recover the closure member so that it will tightly conform to the substrate. In doing so, tensile forces are developed in the closure member which are resisted by the fastening means holding the edges of the closure member fixed relative to one another. In certain of the wrap-around closure devices, the fastening means, in resisting the tensile loading of the recovering closure member, inherently develop twisting moments resulting from a misalignment of the tensile forces induced in the closure member and the resisting forces imposed by the fastening means. In some instances, a resulting twisting of the edge of the closure member allows it to extract itself from the fastening means. To overcome this problem with such wrap-around assemblies, close attention to assembly detail and close tolerances between the closure member and the fastening means are required. All of these difficulties naturally increase the cost of both fabrication and assembly and further increase the possibility of effecting an incomplete closure.